1. Field of the Invention
The present invention relates to a medical system equipped with a medical instrument which drives angles of movable portions such as a bending portion by pulling a wire as well as to a control method.
2. Description of the Related Art
Recently, various medical devices equipped with a bending portion configured to be bendable have been developed. For example, endoscopes and treatment instruments equipped with a bending portion on a distal end side of an insertion portion inserted into a body are widely used in a medical field.
Also, a lesion or the like in the body is treated using a treatment instrument passed into a treatment instrument channel provided in an endoscope. Sometimes treatments are administered with a treatment instrument under observation with an endoscope without using a treatment instrument channel.
Also, an active treatment instrument and the like equipped with driving means (actuator) configured to electrically drive the bending portion to improve operability have been put into actual use. Medical devices such as active treatment instruments provided with a bending portion on a distal end side have a configuration in which the bending portion and the driving means are connected with each other via an angle wire (hereinafter abbreviated to a wire) and the wire is driven by pulling by the driving means provided on a user's hand side to drive the bending portion on the distal end side.
With this configuration, the wire passed through a flexible, elongated member between the bending portion and the driving means on the user's hand side needs to be inserted into a body cavity in a flexed state, which makes it structurally difficult to completely avoid slack in the wire. Also, due to the slack, an amount of driving by the driving means on the user's hand side is not always equal to an amount of operation of the bending portion on the distal end side.
Thus, for example, a first conventional example, namely an endoscope disclosed in Japanese Patent Application Laid-Open Publication No. 2000-300511, is configured to remove slack from a wire by controlling the slack using tension information detected by a tension sensor adapted to detect tension acting on the wire.
Also, a second conventional example, namely a control apparatus disclosed in Japanese Patent Application Laid-Open Publication No. 2007-283115, is configured to remove any wire slack in order to improve responsiveness in driving to bend a bending portion in response to a user's operation command.